Agriculture and Environment: UPSC Previous Year Questions (Environment and Ecology)
16 previous year UPSC Prelims questions on agriculture and the environment are on this page, from 2011 to 2022. UPSC asks about farming practices with environmental effects, such as the System of Rice Intensification, zero tillage, fertigation, biochar, permaculture and conservation agriculture. The explanations give the benefit and the limits of each practice.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 11–16 of 16 questions
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UPSC 2018Environment and Ecology · Agriculture and Environment
Q11. With reference to agricultural soils, consider the following statements: 1. A high content of organic matter in soil drastically reduces its water holding capacity. 2. Soil does not play any role in the sulphur cycle. 3. Irrigation over a period of time can contribute to the salinization of some agricultural lands. Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: Soil water holding capacity is the amount of water that a given soil can hold for crop use. Soil texture and organic matter are the key components that determine soil water holding capacity. Organic matter influences the physical conditions of a soil in several ways.
Statement 2 is incorrect: Sulphur is one of three nutrients that are cycled between the soil, plant matter and the atmosphere. The sulphur cycle describes the movement of sulphur through the atmosphere, mineral and organic forms, and through living things.
Statement 3 is correct: Salinization is a major problem associated with irrigation, because deposits of salts build up in the soil and can reach levels that are harmful to crops.
Exam tip:
S1 and S2 contain extreme phrases like "Drastically reduces" and "any role", hence more probable to be false, instead, S3 contains "some" hence plausible to be true. "Some" = possibility logic, not absolute. If even one species of organism does something, the statement is likely correct.
UPSC 2018Environment and Ecology · Agriculture and Environment
Q12. With reference to the circumstances in Indian agriculture, the concept of "Conservation Agriculture" assumes significance. Which of the following fall under the Conservation Agriculture? 1. Avoiding the monoculture practices 2. Adopting minimum tillage 3. Avoiding the cultivation of plantation crops 4. Using crop residues to cover soil surface 5. Adopting spatial and temporal crop sequencing/crop rotations Select the correct answer using the code given below:
Explanation
Conservation Agriculture (CA) is a farming system that promotes minimum soil disturbance (i.e. no tillage), maintenance of a permanent soil cover, and diversification of plant species. It enhances biodiversity and natural biological processes above and below the ground surface, which contribute to increased water and nutrient use efficiency and to improved and sustained crop production. According to FAO’s website there are three principles of Conservation of Agriculture:
1. Minimum mechanical soil disturbance: It refers to low disturbance no-tillage and direct seeding. The disturbed area must be less than 15 cm wide or less than 25% of the cropped area (whichever is lower).
2. Permanent soil organic cover: Three categories are distinguished: 30-60%, >60-90% and >90% ground cover, measured immediately after the direct seeding operation. An area with less than 30% cover is not considered as CA.
3. Species diversification: Rotation/association should involve at least 3 different crop species. The rotation of crops is not only necessary to offer a diverse "diet" to the soil micro organisms, but as they root at different soil depths, they are capable of exploring different soil layers for nutrients.
UPSC 2017Environment and Ecology · Agriculture and Environment
Q13. Which of the following statements can help in water conservation in agriculture? 1. Reduced or zero tillage of the land 2. Applying gypsum before irrigating the field 3. Allowing crop residue to remain in the field Select the correct answer using the code given below:
Explanation
Efficient water use in agriculture refers to practices and techniques that aim to maximize the productivity of crops while minimizing water consumption. It involves employing methods such as capturing and storing water and drip irrigation to deliver water directly to the plant roots, reducing losses due to evaporation or runoff. Statements 1 and 3 are correct: Conservation Tillage includes no-till farming or zero tillage which is a way of growing crops or pasture from year to year without disturbing the soil through tillage. Zero tillage helps in soil moisture conservation. Crop residues act as mulches and reduce evaporation losses and protect the soil from direct impact of raindrops, thus controlling crusting and sealing processes.
Statement 2 is incorrect: Though, Gypsum helps in dissolution of the salt clay pan found in soils that hinder the percolation of water and helps in water conservation.
UPSC 2015Environment and Ecology · Agriculture and Environment
Q14. What can be the impact of excessive/inappropriate use of nitrogenous fertilizers in agriculture? 1. Proliferation of nitrogen fixing microorganisms in soil can occur. 2. Increase in the acidity of soil can take place. 3. Leaching of nitrate to the groundwater can occur. Select the correct answer using the codes given below.
Explanation
With excessive use of nitrogenous fertilizers in agriculture, the necessity for nitrogen-fixing bacteria decreases as soil nitrogen levels increase. The soil becomes more acidic and nitrate leaches into the groundwater when nitrogenous fertilisers are used excessively or inappropriately. Fertilizers in agriculture increase inputs of nutrients to soils affecting their pH value.
Statement 1 is incorrect: Nitrogen-fixing microorganisms, such as Rhizobium (in leguminous plants), Azotobacter, and Cyanobacteria (blue-green algae) fix atmospheric nitrogen into the soil. But excessive nitrogen fertilizers reduce biological nitrogen fixation because plants get sufficient nitrogen from fertilizers and do not depend on these microbes. Thus instead of increasing, nitrogen-fixing bacteria decrease in population due to reduced plant-microbe symbiosis.
Statement 2 and 3 are correct: The conversion of Nitrogen from one form to the other involves the generation or consumption of acidity and the uptake of urea, ammonium or nitrate by plants will also affect the acidity of the soil. Due to the leaching process, these substances accumulate underground.
Exam tip:
For S1, If plenty of nitrogen is already being dumped into the soil by fertilizers, will the soil "want" microbes to work harder? No. The natural balance gets disturbed. The plant and soil reduce dependency on nitrogen-fixing organisms. In fact, such microbes decline because their service is no longer "in demand." Hence S1 likely false, Eliminating options A and D.
UPSC 2012Environment and Ecology · Agriculture and Environment
Q15. Consider the following agricultural practices: 1. Contour bunding 2. Relay cropping 3. Zero tillage In the context of global climate change, which of the above helps/ help in carbon sequestration/storage in the soil?
Explanation
Terrestrial Carbon sequestration is the process through which carbon dioxide from the atmosphere is absorbed by trees and plants through photosynthesis and stored as carbon in soil and biomass. Option 3 is correct: Zero Tillage is the process where the crop seed will be sown through drillers without prior land preparation and distributed in the soil where previous crop stubbles are present. Zero tillage not only reduces the cost of cultivation it also reduces the soil erosion, crop duration, irrigation requirement and weed effect which is better than tillage. Zero tillage is environmentally safe because it helps in reducing greenhouse effect through carbon sequestration. Options 1 and 2 are incorrect:
Contour bundling involves the construction of banks along the contours. Terracing and contour bunding divide the hill slope into numerous small slopes, check the flow of water, promote absorption of water by soil and save soil from erosion. Retaining walls of terraces control the flow of water and help in reducing soil erosion. Relay Cropping is the process of growing one crop, then planting another crop (usually a cover crop) in the same field before harvesting the first. This helps avoid competition between the main crop and the intercrop. It also uses the field for a longer time, since the cover crop usually continues to grow after the main crop is harvested.
UPSC 2011Environment and Ecology · Agriculture and Environment
Q16. With reference to micro-irrigation, which of the following statements is/are correct? 1. Fertilizer/nutrient loss can be reduced. 2. It is the only means of irrigation in dryland farming. 3. In some areas of farming, the receding of groundwater tables can be checked. Select the correct answer using the codes given below:
Explanation
Micro-irrigation is the slow distribution of water to the soil using surface drip and micro-sprinkler systems in the form of discrete or continuous drips, tiny streams, or miniature spray. Benefits of micro irrigation systems: Helps in water-saving and checking further depletion, Increased irrigation efficiency, Higher yields, Less water loss, Energy efficient, Lower consumption of fertilizers, Weed and disease reduction, Cost savings, Precision farming.
Statement 1 is correct: An efficient drip irrigation system reduces the consumption of fertiliser through fertigation.
Statement 2 is incorrect: Dryland farming is defined as the production of crops without irrigation in regions that receive rainfall of less than 500mm annually. Crop selection, Microcatchments and Runoff farming are some other methods of irrigation in dry-land farming.
Statement 3 is correct: Micro-irrigation helps in water-saving and checking further groundwater depletion.
Answer key for these questions
Q
UPSC year
Correct answer
11
2018
(b) 3 only
12
2018
(c) 2, 4 and 5
13
2017
(c) 1 and 3 only
14
2015
(c) 2 and 3 only
15
2012
(b) 3 only
16
2011
(c) 1 and 3 only
What UPSC has tested in Agriculture and Environment
Rice is the most important anthropogenic source of both methane and nitrous oxide among the crops asked.
The System of Rice Intensification uses alternate wetting and drying and lowers water use and methane emissions.
Biochar can be used as part of the growing medium and improves soil carbon; zero tillage lets wheat be sown without preparing the land.
Carbon fertilization is increased plant growth due to a higher level of carbon dioxide.
Carbofuran, methyl parathion, phorate and triazophos are pesticides viewed with concern in India.
Frequently asked questions
How many previous year UPSC questions are there on Agriculture and Environment?
This page covers 16 previous year UPSC Prelims GS Paper-I questions on Agriculture and Environment (Environment and Ecology), asked from 2011 to 2022. Each has the correct answer and an explanation.
Which crop is a major source of methane and nitrous oxide?
Rice. Flooded paddy fields produce methane in oxygen-poor soil, and nitrogen fertiliser applied to the crop releases nitrous oxide, so rice cultivation is a major agricultural source of both greenhouse gases.
What is zero tillage?
Sowing a crop directly into the stubble of the previous one without ploughing. It saves fuel, time and moisture, lets wheat be sown early after rice, and reduces soil erosion and emissions.
What is biochar?
A charcoal-like material made by heating biomass with little oxygen. Added to soil, it improves water retention and soil structure and locks carbon in the soil for a long time, so it acts as a carbon sink.
